nvme-fabrics: fix and refine state checks in __nvmf_check_ready

 - make sure we only allow internally generates commands in any non-live
   state
 - only allow connect commands on non-live queues when actually in the
   new or connecting states
 - treat all other non-live, non-dead states the same as a default
   cach-all

This fixes a regression where we could not shutdown a controller
orderly as we didn't allow the internal generated Property Set
command, and also ensures we don't accidentally let a Connect command
through in the wrong state.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Smart <james.smart@broadcom.com>